Electrical characterization of low temperature He-ion irradiated GaN

Abstract

In this paper, we report on the modification of the mobility and carrier concentration due to low temperature (25 K) 5.4 MeV He-ion irradiation of n-type GaN. Both the mobility and the carrier concentration were reduced as a result of the incident high energy He-ions. It is known from DLTS measurements that electrically active defects are introduced during such an irradiation process. In an attempt to thermally remove the defects in order to see if the material recovered to its original specifications, it was subjected to isochronal annealing up to 443 K. We observed very little recovery, leading us to conclude that the defects causing the degradation of the mobility and carrier concentration are thermally stable up to the anneal temperatures used here. There was very little change in the peak mobility temperature as a function of incident He-ion fluence.